7
Iris and Pupils
Relative Afferent Pupillary Defect
Mesodermal Dysgenesis Syndromes
Trauma
Definition
Angle Recession
Tear in ciliary body between longitudinal and circular muscle fibers. Appears as broad blue-gray band (ciliary body) on gonioscopy; associated with hyphema at time of injury. If more than two-thirds of the angle is involved, 10% develop glaucoma from scarring of angle structures.
Cyclodialysis
Disinsertion of ciliary body from scleral spur. Appears as broad white band (sclera) on gonioscopy; associated with hyphema at time of injury; may develop hypotony.
Iridodialysis
Disinsertion of iris root from ciliary body. Appears as peripheral iris hole; associated with hyphema at time of injury.
Sphincter Tears
Small radial iris tears at pupillary margin. May be associated with hyphema at time of injury; may result in permanent pupil dilation (traumatic mydriasis) and anisocoria.
Symptoms
Pain, photophobia, red eye; may have decreased vision, monocular diplopia or polyopia.
Signs
Normal or decreased visual acuity, conjunctival injection, subconjunctival hemorrhage, anterior chamber cells and flare, hyphema, unusually deep anterior chamber, iris tears, abnormal pupil, angle tears, iridodonesis, increased or decreased intraocular pressure; may have other signs of ocular trauma including lid or orbital trauma, dislocated lens, phacodonesis, cataract, vitreous hemorrhage, commotio retinae, retinal tear or detachment, choroidal rupture, or traumatic optic neuropathy; may have signs of glaucoma with increased intraocular pressure, optic nerve cupping, nerve fiber layer defects, and visual field defects.
Differential Diagnosis
See above, distinguish by careful gonioscopy; also, surgical iridectomy or iridotomy, iris coloboma, essential iris atrophy, Reiger’s anomaly.
Evaluation
• Check the angle with gonioscopy and rule out retinal tears or detachment with scleral depression if the globe is intact and there is no hyphema.
• B-scan ultrasonography if unable to visualize the fundus. Consider ultrasound biomicroscopy to evaluate angle structures and localize the injury.
• Rule out open globe and intraocular foreign body (see Chapter 4).
Prognosis
Depends on amount of damage; poor when associated with angle recession glaucoma or chronic hypotony.
Corectopia
Definition
Displaced, ectopic, or irregular pupil.
Etiology
Mesodermal dysgenesis syndromes, iridocorneal endothelial (ICE) syndromes, chronic uveitis, trauma, postoperative, ectopia lentis et pupillae (corectopia associated with lens subluxation).
Symptoms
Asymptomatic; may have glare or decreased vision.
Signs
Normal or decreased visual acuity; distorted, malpositioned pupil.
Evaluation
• Rule out open globe (peaked pupil after trauma, see Chapter 4).
Prognosis
Depends on etiology and degree of malposition (distance from visual axis). Usually benign if mild, isolated, and nonprogressive (i.e., postoperative). However, if associated with other findings or progressive, visual loss can occur.
Seclusio Pupillae
Definition
Posterior synechiae (iris adhesions to the lens) at the pupillary border for 360°.
Etiology
Inflammation (anterior uveitis, see Chapter 6).
Symptoms
Asymptomatic; may have pain, red eye, and decreased vision.
Signs
Normal or decreased visual acuity, posterior synechiae, poor or irregular pupil dilation, increased intraocular pressure, acute or chronic signs of iritis, including anterior chamber cells and flare, keratic precipitates, iris atrophy, iris nodules, cataract, and cystoid macular edema.
Differential Diagnosis
Occlusio pupillae (fibrotic membrane across the pupil), persistent pupillary membrane.
Evaluation
• Consider anterior uveitis workup (see Chapter 6).
Prognosis
Depends on etiology; poor if glaucoma has developed.
Peripheral Anterior Synechiae
Definition
Peripheral iris adhesions to the cornea or angle structures; extensive peripheral anterior synechiae can cause increased intraocular pressure and angle-closure glaucoma.
Etiology
Peripheral iridocorneal apposition due to previous pupillary block, flat or shallow anterior chamber, or inflammation.
Symptoms
Asymptomatic; may have symptoms of angle-closure glaucoma (see Chapter 6).
Signs
Iris adhesions to Schwalbe’s line and cornea; may have signs of angle-closure glaucoma with increased intraocular pressure, optic nerve cupping, nerve fiber layer defects, and visual field defects.
Differential Diagnosis
Iris processes (mesodermal dysgenesis syndromes [see below]).
Evaluation
• Check visual fields in patients with elevated intraocular pressure or optic nerve cupping to rule out glaucoma.
Prognosis
Usually good; depends on extent of synechial angle closure and intraocular pressure control.
Rubeosis Iridis
Definition
Neovascularization of the iris and angle.
Etiology
Ocular ischemia; most commonly occurs with proliferative diabetic retinopathy, central retinal vein occlusion, and carotid occlusive disease; also associated with anterior segment ischemia, chronic retinal detachment, tumors, sickle cell retinopathy, chronic inflammation, and other rarer causes.
Symptoms
Can be asymptomatic if no angle involvement; angle involvement may lead to neovascular glaucoma (see below) with decreased vision or other symptoms of angle-closure glaucoma (see Chapter 6).
Signs
Normal or decreased visual acuity, abnormal blood vessels on iris and angle, particularly at pupillary margin and around iridectomies; may have spontaneous hyphema, or retinal lesions; may have signs of angle-closure glaucoma with increased intraocular pressure, optic nerve cupping, nerve fiber layer defects, and visual field defects.
Differential Diagnosis
See above.
Evaluation
• Check visual fields in patients with elevated intraocular pressure or optic nerve cupping to rule out glaucoma.
• Consider fluorescein angiogram to narrow differential diagnosis and determine cause of ocular ischemia if not apparent on direct examination.
• Consider medical consultation for systemic diseases including duplex and Doppler scans of carotid arteries to rule out carotid occlusive disease.
Prognosis
Poor; the rubeotic vessels may regress with appropriate therapy, but most causes of neovascularization are chronic progressive diseases.
Neovascular Glaucoma
Definition
A form of secondary angle-closure glaucoma in which neovascularization of the iris and angle causes occlusion of the trabecular meshwork.
Etiology
Any cause of rubeosis iridis (see above).
Symptoms
Decreased vision and symptoms of angle-closure glaucoma (see Chapter 6).
Signs
Decreased visual acuity; abnormal blood vessels on iris and angle, particularly at pupillary margin and around iridectomies; increased intraocular pressure, optic nerve cupping, nerve fiber layer defects, and visual field defects; may have corneal edema, spontaneous hyphema, or retinal lesions.
Differential Diagnosis
As for rubeosis iridis (see above), and other forms of secondary angle-closure glaucoma (see Chapter 6).
Evaluation
• Check visual fields.
• Consider fluorescein angiogram to narrow differential diagnosis and determine cause of ocular ischemia if not apparent on direct examination.
• Consider medical consultation for systemic diseases, including duplex and Doppler scans of carotid arteries to rule out carotid occlusive disease.
Prognosis
Poor; the rubeotic vessels may regress with appropriate therapy, but most causes of neovascularization are chronic progressive diseases.
Pigment Dispersion Syndrome
Definition
Liberation of pigment from the iris with subsequent accumulation on anterior segment structures.
Etiology
Chafing of posterior iris surface on zonules produces pigment dispersion.
Epidemiology
More common in 20- to 50-year-old Caucasian men and in patients with myopia; affected women are usually older; associated with lattice degeneration in 20% of cases and retinal detachment in up to 5% of cases; 25–50% develop pigmentary glaucoma. Mapped to chromosome 7q35-q36 (GPDS1 gene).
Symptoms
Asymptomatic; exercise or pupil dilation can cause pigment release with acute elevation of intraocular pressure and symptoms including halos around lights and blurred vision.
Signs
Radial, midperipheral, iris transillumination defects, pigment on corneal endothelium (Krukenberg spindle), posterior bowing of midperipheral iris, dark pigment band overlying trabecular meshwork, pigment in iris furrows and on anterior lens capsule; may have signs of glaucoma with increased intraocular pressure, optic nerve cupping, nerve fiber layer defects, and visual field defects (see below); may have pigmented anterior chamber cells, especially following pupil dilation.
Differential Diagnosis
Uveitis, albinism, pseudoexfoliation syndrome, iris atrophy.
Evaluation
• Check visual fields in patients with elevated intraocular pressure or optic nerve cupping to rule out glaucoma.
Prognosis
Usually good; poorer if pigmentary glaucoma develops.
Pigmentary Glaucoma
Definition
A form of secondary open-angle glaucoma caused by pigment liberated from the posterior iris surface (i.e., a sequela of uncontrolled increased intraocular pressure in pigment dispersion syndrome).
Epidemiology
Develops in 25% to 50% of patients with pigment dispersion syndrome; same associations as in pigment dispersion syndrome (see above). Mapped to chromosome 7q35-q36.
Mechanism
Obstruction of the trabecular meshwork by dispersed pigment and pigment-laden macrophages.
Symptoms
Asymptomatic; may have decreased vision or constricted visual fields in late stages; exercise or pupil dilation can cause pigment release with acute elevation of intraocular pressure and symptoms including halos around lights and blurred vision.
